Wyniki wyszukiwania - Biblioteka Nauki

1

Analysing the impact of dependency on conditional survival functions using copulas

100%

Safari-Katesari H. , Zaroudi S.

Statistics in Transition new series

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2021

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tom 22

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nr 1

217-226

EN

Nowadays, insurance contract reserves for coupled lives are considered jointly, which has a significant influence on the process of determining actuarial reserves. In this paper, conditional survival distributions of life insurance reserves are computed using copulas. Subsequently, the results are compared with an independence case. These calculations are based on selected Archimedean copulas and apply when the 'death of one individual' condition exists. The estimation outcome indicates that the insurer reserves calculated by means of Archimedean copulas are far more effective than those resulting from an independence assumption. The study demonstrates that copula-based dependency modelling improves the calculations of reserves made for actuarial purposes.

2

Direct interaction between micronutrients and bell pepper (Capsicum annum L.), to affect fitness of Myzus persicae (Sulzer)

86%

Alizamani T. , Shakarami J. , Mardani-Talaee M. , Zibaee A. , Serrão J. E. , Alizamani T. , Shakarami J. , Mardani-Talaee M. , Zibaee A. , Serrão J. E.

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3

Effects of different kairomonal sources on the performance of Eretmocerus sp. near furuhashii against Bemisia tabaci on cucumber: II - in greenhouse

86%

Mandour N. S. , Ren S.-x. , Qiu B.-l. , Wäckers F.

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4

Comparative Analysis of FDI Duration in the Visegrád Group Member States, Using Mortality Tables: A Sectoral Approach

72%

Salamaga M.

Econometrics. Ekonometria. Advances in Applied Data Analytics

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2022

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tom 26

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nr 2

1-15

PL

Bezpośrednie inwestycje zagraniczne są uruchamiane w określonym momencie przez inwestorów, trwają pewien czas, a potem mogą zostać zakończone lub trwają dalej. Mogą zatem występować obserwacje zarówno kompletne, jak i ucięte, podobnie jak w analizach procesów ludnościowych, stąd zastosowanie metod demograficznych do badania przeżywalności projektów BIZ jest uzasadnione. Celem artykułu jest przedstawienie specjalnie skonstruowanych tablic trwania życia BIZ i porównanie wzorców „przeżywalności” bezpośrednich inwestycji zagranicznych według wybranych sektorów gospodarczych w krajach Grupy Wyszehradzkiej. Kraje te od lat cieszą się dużym zainteresowaniem inwestorów zagranicznych i często rywalizują ze sobą o nowe projekty BIZ. Stąd porównanie ich nie tylko pod względem procesów związanych z napływem BIZ, ale i pod względem procesów dezinwestycji wydaje się intersujące i ważne zarówno dla ekonomistów, analityków rynku, jak i dla samych inwestorów. W badaniu wykorzystano dane pochodzące z baz danych Orbis oraz Zephyr.

EN

FDIs are an important part of the 'bloodstream' of many countries' economies, and it would be difficult to overestimate the benefits of FDIs for the states that receive them. The processes of FDI influx and their effects have been the subject of numerous studies and analyses in the fields of both economic theory and empirical research. However, less attention has been paid to the process of divestment, which in many cases may result in adverse changes in the economies of FDI recipient countries. This article proposes that event history analysis methods can be used to study the survival of FDI projects. FDIs are launched at a certain point in time by investors, last for some time, and then can be either terminated or continued. In this context, we may come across complete as well as truncated observations, much like in the analyses of population processes, therefore the use of demographic methods to study the survivability of FDI projects is justified. The purpose of this article was to present specially constructed FDI life tables and to compare the 'survivability' patterns of foreign direct investments in selected economic sectors of the Visegrád Group countries. For many years, these countries have enjoyed considerable interest from foreign investors and have often competed with each other for new FDI projects. Therefore, comparing them not only in terms of the processes related to FDI influx, but also in terms of the processes of divestment appears interesting and important to economists, market analysts and the investors themselves. The study used data from the Orbis and Zephyr databases.

5

Plasticity in dynamics and hygrochastic persistence in Anastatica hierochuntica (Brassicaceae) populations under simulated rainfall treatments

72%

Hegazy A. K. , Kabiel H. F. , Alatar A. A. , Lovett-Doust J.

Polish Journal of Ecology

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2013

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tom 61

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nr 3

EN

Anastatica hierochuntica is a monocarpic desert annual whose dry skeletons, enclosing mature fruits, often persist for a number of years. The aerial seed bank in these hygrochastic ‘resurrection plants’ therefore persists too. Life tables and fecundity schedules were constructed for A. hierochuntica populations raised under four water treatments, equivalent to 100, 200, 500 and 1000 mm rainfall. Seedling survivorship showed a Deevey type III curve for 100 mm, and a type II curve for 200 mm, while 500 and 1000 mm treatments produced Deevey type I curves. Fewer seeds germinated and seedling survivorship was lower in the low water treatments. The stage-specific mortality rate reached 0.75 under the 100 mm treatment in the seed germination stage, compared to 0.08 under the 1000 mm treatment. Increased water availability resulted in greater plant growth and reproductive output, in terms of both number of seeds per individual and reproductive value. In field studies, aerial seed banks of small plant sizeclasses (from 1 to 32 cm³) were depleted within 3-to-7 years. For the large size-classes, > 32 cm³, only a portion (79.7-44.4%) of the seeds produced were dispersed during the observational experiment (the rest remaining within the tumbleweed ball, available for subsequent germination). The projected seed bank life-time for populations raised under different water treatments increased more than fivefold (from 3 to 17 years) for the 100 mm compared to the 1000 mm rainfall treatments. Local persistence of populations was thus likely to be reduced by water stress. Populations of A. hierochuntica characterized by weak plant growth and a preponderance of small size-classes will be more vulnerable to extinction due to their low reproductive output and reduced aerial seed bank reserve.

6

Plasticity in dynamics and hygrochastic persistence in Anastatica hierochuntica (Brassicaceae) populations under simulated rainfall treatments

58%

Hegazy A. K. , Kabiel H. F. , Alatar A. A. , Lovett-Doust J.

Polish Journal of Ecology

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2013

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tom Vol. 61, nr 3

493--504

EN

Anastatica hierochuntica is a monocarpic desert annual whose dry skeletons, enclosing mature fruits, often persist for a number of years. The aerial seed bank in these hygrochastic ‘resurrection plants’ therefore persists too. Life tables and fecundity schedules were constructed for A. hierochuntica populations raised under four water treatments, equivalent to 100, 200, 500 and 1000 mm rainfall. Seedling survivorship showed a Deevey type III curve for 100 mm, and a type II curve for 200 mm, while 500 and 1000 mm treatments produced Deevey type I curves. Fewer seeds germinated and seedling survivorship was lower in the low water treatments. The stage-specific mortality rate reached 0.75 under the 100 mm treatment in the seed germination stage, compared to 0.08 under the 1000 mm treatment. Increased water availability resulted in greater plant growth and reproductive output, in terms of both number of seeds per individual and reproductive value. In field studies, aerial seed banks of small plant size-classes (from 1 to 32 cm3) were depleted within 3-to-7 years. For the large size-classes, > 32 cm3, only a portion (79.7-44.4%) of the seeds produced were dispersed during the observational experiment (the rest remaining within the tumbleweed ball, available for subsequent germination). The projected seed bank life-time for populations raised under different water treatments increased more than fivefold (from 3 to 17 years) for the 100 mm compared to the 1000 mm rainfall treatments. Local persistence of populations was thus likely to be reduced by water stress. Populations of A. hierochuntica characterized by weak plant growth and a preponderance of small size-classes will be more vulnerable to extinction due to their low reproductive output and reduced aerial seed bank reserve.

7

Effect of temperature and relative humidity on population parameters for almond moth (Cadra cautella Wlk.) (Lepid. Phycitidae)

58%

Nawrot J.

Prace Naukowe Instytutu Ochrony Roślin

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1979

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tom 21

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nr 2

8

Effect of different kairomonal sources on the performance of Eretmocerus sp. near furuhashii against Bemisia tabaci on cucumber: II - In greenhouse

58%

Mandour N. S. , Ren S. , Qiu B. , Wackers F.

Journal of Plant Protection Research

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2007

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tom 47

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nr 3

289-298

EN

The effects of application of an artificial honeydew mixture of glucose, fructose and trehalose (GFT), honey and Bemisia tabaci nymph-extract as kairomonal sources in enhancing the foraging efficiency and performance of Eretmocerus sp. near furuhashii on cucumber plants were studied. Experiments were conducted in small greenhouses (4x3*3 m) using life table methods. Life table data indicated that the total mortality in B. tabaci immature cohorts in all treatments was in the order of fourth instar > first instar > second = third > egg > pupa cohorts. The tested kairomonal materials had a significant effect on the rate of parasitism (p > 0.0415) with 13.23, 9.04 and 10.54% higher than that of control in artificial honeydew of GFT, nymph-extract and honey treatments, respectively. B. tabaci egg/adult survival ratio was also significantly affected (p > 0.0001) by the tested kairomonal sources being lowest (22.91%) in nymph-extract treatment. Moreover, the tested kairomonal materials arrested significantly more parasitoids to colonize the treated plants comparing to control. Apparently, the tested materials were significantly effective in attracting the parasitoids up to 3 days after applications then significant difference was not found between treatments.

PL

Badano skutki zastosowania sztucznej mieszaniny glukozy, fruktozy i trehalozy (GFT) imitującej spadź oraz miodu i ekstraktu z nimf Bemisia tabaci na ogórku jako źródła kairomonów dla zwiększenia poszukiwania pożywienia i występowania gatunku Erethmocerus near furuhashi. Eksperymenty przeprowadzono w małych szklarniach (4x3x3 m) posługując się metodą 'life table'. Dane uzyskane za pomocą tej metody wykazały, że ogólna śmiertelność w niedojrzałych kohortach B. tabaci malała następująco: czwarte stadium > pierwsze stadium > drugie = trzecie > jajo > poczwarka. Testowane preparaty kairomonowe miały istotny wpływ na stopień pasożytowania (p > 0.0415), który był wyższy niż w przypadku kontroli odpowiednio o 13,23%, 9,04% i 10,54% dla sztucznej spadzi, ekstraktu z nimf i miodu. Znaczny także był wpływ źródeł kairomonów na stosunek przetrwania jajo/dorosły osobnik B. tabaci (p > 0,0001), a najniższy (22,91%) zaobserwowano w przypadku ekstraktu z nimf. Ponadto, preparaty kairomonowe przyciągnęły znacznie więcej parazytoidów do roślin traktowanych niż do kontrolnych. Testowane preparaty działały efektywnie do trzech dni po ich zastosowaniu.

9

Population parameters for almond moth (Cadra cautella Wlk.) (Lepidoptera: Phycitidae) reared on natural products

51%

Nawrot J.

Prace Naukowe Instytutu Ochrony Roślin

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1979

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tom 21

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nr 2